# Nucleation and growth bottleneck in the conductivity recovery dynamics of nickelate thin films

## TL;DR

This study explores the ultrafast conductivity recovery in nickelate thin films after thermal quenching, revealing distinct dynamics in different compounds and potential for rapid electronic switching.

## Contribution

It demonstrates that NdNiO$_3$ exhibits non-exponential, first-order recovery dynamics well-described by a 2D Avrami model, highlighting phase coexistence and supercooling effects.

## Key findings

- NdNiO$_3$ shows non-exponential, slower recovery.
- EuNiO$_3$ exhibits exponential recovery.
- Large transient responses suggest fast switching potential.

## Abstract

We investigate THz conductivity dynamics in NdNiO$_3$ and EuNiO$_3$ thin films following a photoinduced thermal quench into the metallic state and reveal a clear contrast between first- and second-order dynamics. While in EuNiO$_3$ the conductivity recovers exponentially, in NdNiO$_3$ the recovery is non-exponential and slower than a simple thermal model. Crucially, it is consistent with first-order dynamics and well-described by a 2d Avrami model, with supercooling leading to metastable phase coexistence. The large transients seen in our films are promising for fast electronic (and magnetic) switching applications.